Carrier aggregation of a long term evolution (LTE) system may be roughly classified into carrier aggregation in a base station and carrier aggregation between base stations. Cell aggregation in a base station is controlled by only one base station and therefore is relatively simple. The “Release-10” release of the third generation partnership project (3GPP) supports the carrier aggregation in a base station but does not support the carrier aggregation between base stations yet. The carrier aggregation between base stations may be further classified into carrier aggregation between macro base stations and carrier aggregation between a macro base station and a small-cell base station. The carrier aggregation between base stations is also referred to as dual connectivity or multiple stream aggregation (MSA), that is, a user equipment (UE) may simultaneously receive data from two or more base stations.
At present, in the carrier aggregation between base stations, base stations are classified into a primary base station and a secondary base station, where the primary base station is mainly responsible for implementing a control function and transmitting some data, and the secondary base station is mainly configured to offload data. If the primary base station decides to hand over a bearer from one base station (for example, the primary base station) to another base station (for example, the secondary base station), a path switch procedure needs to be performed to complete a path switch. At present, a path switch technology is mainly applied to an X2 handover.
However, the carrier aggregation between base stations is different from the X2 handover. A secondary evolved node B (eNB) may be a small-cell base station, during the carrier aggregation between base stations, each bearer handover requires a path switch procedure. Therefore, a possibility of occurrence of a path switch is far greater than that of the X2 handover, and frequent path switches easily cause network security to be out of synchronization, resulting in a call drop of a UE.